1. Field of the Invention
The present invention relates to an igniter for igniting material and, in particular, to an igniter for igniting gas generating material in an inflatable occupant restraint system for a vehicle.
2. Description of the Prior Art
Igniters for igniting a gas generating material in an inflatable occupant restraint system for a vehicle are known. One such igniter is disclosed in U.S. Pat. No. 4,706,990. The igniter disclosed in U.S. Pat. No. 4,706,990 includes an impact sensor operatively connected with one end of a pyrotechnic transmission line. The pyrotechnic transmission line is connected at its other end to an inflator for the inflatable occupant restraint system. During a vehicle collision, the inertia of a moving mass in the impact sensor causes a firing pin to ignite an explosive primer. The explosive primer, when ignited, produces a shock wave which ignites the pyrotechnic transmission line which, in turn, ignites gas generating material in the inflator to rapidly generate gas to fill an inflatable restraint.
Another igniter for igniting gas generating material in a vehicle safety system is disclosed in U.S. Pat. No. 4,178,016. The igniter disclosed in U.S. Pat. No. 4,178,016 includes a crash sensor which provides an electrical signal to heat and ignite a primer. The primer then ignites a fuse cord which burns at a relatively high velocity toward a pyrotechnic charge to ignite the pyrotechnic charge. Gas generated by the ignition of the pyrotechnic charge drives a motor to tighten a seat belt against a vehicle occupant.
U.S. Pat. No. 3,754,506 discloses a detonator in which a loosely packed portion of explosive powder is located between an annular electrode and a central electrode. A spark is generated between the annular electrode and the central electrode to ignite the loosely packed explosive powder which, in turn, ignites an adjacent and more densely packed portion of the explosive powder.